I'd love to repair my old Samsung UN55H7150 LED TV to pass it on to my grandma. Her vision is worsening, and this would be a nice upgrade over her 24" tube TV in her bedroom.

About a year ago, the TV would randomly loop the "Smart TV" startup logo. I'd power on the TV, and as the "Smart TV" logo would load, the TV would power off / on and this would repeat for a random extended period of time. This would last anywhere from a few minutes to 15+ minutes, until it would completely power on and continue to work fine until it was turned off. This issue lasted for a couple of months.

Eventually that stopped and it started to just load the "Smart TV" logo once and then the TV would go black. At that point the light at the bottom is red, and it won't react to any buttons being pressed, and won't power off until the unit is unplugged.

I'm a newbie, but I'm assuming that one of its' boards went bad. Anyone know which board is the culprit? Or suggestions on ways to diagnosis and confirm which one is causing the problem?